The present disclosure finds its genesis in finding efficiencies for human movement. Specifically, facilitation of human activities more easily is the ultimate goal of numerous researchers. Research has led to numerous devices and approaches to aid in increasing speed of motion, weight compensation, metabolic rate reduction, and other aspects that allow a human body to function more efficiently.
Although all of the above-mentioned applications are very important, in recent years, metabolic rate reduction during cyclic tasks (especially walking and running) has gained much attention among the other researches. Accordingly, different types of lower limb exoskeletons are designed to decrease the metabolic rate in running or walking. These exoskeletons may be categorized from different perspectives based on their energy usages. Accordingly, we have two different types of exoskeletons: powered and unpowered. The powered exoskeletons utilize motors and actuators in order to exert the assistive forces/torques; however, the unpowered exoskeletons do not have any actuator or electrical element which consume energy. A class of unpowered exoskeletons are unpowered compliant exoskeletons (UCEs) which relay on their elastic structures in order to facilitate a user's motions. Elastic element of the UCEs absorb a part of energy in a phase of motion and recycle it on the other phase. By doing so, some of dissipated energies can be reused in the cycle of motion, and muscles' activities are minimized. As a result, the metabolic energy consumption during the task is reduced. Although, the UCEs cannot provide the supportive torque as best as powered ones, their worthy features as needless to power supply, easy use, simple design, low construction cost, and light weight encourages the researchers to put effort on design of this category. As it is mentioned, one of the current challenges in UCE design, is metabolic rate reduction in walking and running. However, these traditional UCE's have a limitation that they minimize metabolic rate in walking. Nevertheless, conventional running exoskeletons don't have that much success in reducing metabolic rate of running.
During past years, physiologists understand that, in walking, the most contributing joints and muscles are ankles and Achilles which insert highest torque at the push-off instance. It is also observed that (except the push-off moment) in the rest of a stride lower limb muscles (compared to push-off moment) are almost inactive. This is the biological reason behind the fact that the most effective exoskeletons in walking are which provide torque at the push-off moment. Nevertheless, these exoskeletons are not effective in the running gait. Although walking and running have many similarities in kinematic point of view, they have significant differences in dynamics and muscles' activities perspectives. Unlike walking, in running the contribution of ankle and hip joints are almost equal, and in sprint running, the hip joints have the most contribution. Hence, in order to reduce the metabolic rate in the running gait, the hip joints must be supported the most.
Therefore, there is a need for an exoskeleton that can augment running that overcomes or minimizes the above-referenced difficulties. Exemplary embodiments described below provide an unpowered compliant exoskeleton which assists the hip joints during running.